A few years ago, a group of Spanish researchers discovered a new reproductive strategy in the red frog, Rana temporaria , a common species in Europe and northwest Asia. Once the female has laid and abandoned the eggs already fertilized by a male, another of the same species proceeds to spray them with his sperm. The objective of the sexual pirate is none other than to fertilize the eggs that did not receive the seed of his competitor and thus perpetuate his genes.
Another similar pillaging maneuver in this type of amphibian is practiced by some male specimens of the North American green frog Hyla cinerea . During the mating season, there are males who stand silently next to others who croak loudly to attract females. When one of them approaches the singer, the quiet specimen steps forward and hugs her quickly. Experts believe that, surely, these fertilization tactics can occur due to the shortage of females.
